1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly to a thermo-transfer type image forming apparatus which produces a copy of image information shown on a document by reading that image information and performing the thermo-transfer of dyeing materials (ink) of different colors onto the read image information medium.
2. Description of the Related Art
In general, a multicolored image forming apparatus includes: an image-reading section for reading image information, e.g., character and graphic data, shown on a document; an image-processing section for converting image information into electric signals in such a manner as to enhance the quality of the image such as sharpness, resolution, tone reproduction, color reproduction, and edge enhancement; an image-forming section for transferring the image information onto an image-bearing medium, i.e., a paper sheet or the like.
The image-reading section is provided with a control panel. A printing start signal, and printing condition-designating signals, such as a signal for designating the number of printing to be produced, a printing magnification signal, and a printing mode signal, are entered from the control panel. The image-reading section is also provided with a document table on which a document is mounted; an illuminating device for illuminating the document mounted on the document table; and a photoelectric conversion unit for converting the light reflected by the document into electric signals. The light reflected by the document represents the image information shown on the document.
The image-processing section is provided with a plurality of electric circuits and control units. For example, the image-processing section is provided with an image-processing circuit for supplying the electric signals obtained by the photoelectric conversion unit to the image-forming section as printing signals, and a main control unit for driving the image-processing circuit and controlling the operation of the entire image-forming apparatus.
The image-forming section is provided with a printing unit for transferring dyeing materials (ink) of different colors onto a paper sheet in accordance with the printing signals supplied from the image-processing section. The image-forming section is also provided with a material-delivering mechanism for delivering the paper sheet to the printing unit, and for discharging the paper sheet from the printing unit after the printing unit transfers the dye materials.
In the above multicolored image-forming apparatus, the image-reading section incorporates a color separation mechanism. This color separation mechanism is made up of optical elements (such as color separation filters of three types, corresponding to the three primary colors of light, focusing lenses, and folding mirrors); and an image-reading device constituted by a CCD sensor. After being read by the image-reading section, the image information shown on the document is converted into electric signals. These electric signals are supplied to the image-processing section as image signals.
In the image-processing section, the image signals are subjected to the image quality enhancement processing, such as intensity correction, edge correction and color correction, in units of each chromatic component. Then, the image signals are converted into color signals in units of each chromatic component, such that the color signals represent colors which are complementary to the colors of the images shown on the document. The color signals are binary-encoded or image-processed in a suitable method, such that tone information is added thereto. Thereafter, the color signals are supplied to the printing unit of the image-forming section as printing signals.
In the printing unit, a printing head corresponding to the printing signals is actuated and, therefore, transfers the ink from a dyeing material carrier to the paper sheet. The dyeing material carrier is moved through the region between the head and the paper sheet, and the paper sheet is maintained at the printing start position before the actuation of the head.
The transfer of ink from the dyeing material carrier to the paper sheet is repeated in accordance with the number of color signals supplied to the printing unit. Since different ink are superposed on the paper sheet, a multicolored image is formed on the paper sheet.
The image-forming apparatus of the above type is provided with various printing modes, such as a trimming mode wherein only a desired portion on a document is printed, a masking mode wherein an undesired portion is not printing, an edit mode wherein only a desired portion is printing onto that portion on a paper sheet which is designated by the user, and a photograph mode wherein halftone reproduction is improved.
The image-forming apparatus is also provided with an large number of keys on the control panel, in order for the user to enter various commands in accordance with the modes.
Since the image-forming apparatus has various modes and since the user has to enter various commands before starting a printing operation, it is likely that the user will make an error when entering the commands or following the printing-producing procedures. Even if the user becomes aware of an error, the user enter the commands associated with a selected mode. Alternatively, the user must cancel the operating mode and restart the entering of commands. In either case, the command entry is difficult to operate for the user.
Since a certain time is required before actually starting the copying operation, the image-forming apparatus does not ensure an efficient printing operation. In addition, since the command entry is difficult to operate for the user, the rate of operation of the image-forming apparatus is degraded, thus increasing the cost needed for producing printing. Further, the user may not make the most of the operating modes of the image-forming apparatus, due to the annoying command entry.